Homoharringtonine synergizes with quizartinib in FLT3-ITD acute myeloid leukemia by targeting FLT3-AKT-c-Myc pathway

Homoharringtonine: updated insights into its efficacy in hematological malignancies, diverse cancers and other biomedical applications

HHT has emerged as a notable compound in the realm of cancer treatment, particularly for hematological malignancies. Its multifaceted pharmacological properties extend beyond traditional applications, warranting an extensive review of its mechanisms and efficacy. This review aims to synthesize comprehensive insights into the efficacy of HHT in treating hematological malignancies, diverse cancers, and other biomedical applications. It focuses on elucidating the molecular mechanisms, therapeutic potential, and broader applications of HHT. A comprehensive search for peer-reviewed papers was conducted across various academic databases, including ScienceDirect, Web of Science, Scopus, American Chemical Society, Google Scholar, PubMed/MedLine, and Wiley. The review highlights HHT's diverse mechanisms of action, ranging from its role in leukemia treatment to its emerging applications in managing other cancers and various biomedical conditions. It underscores HHT's influence on cellular processes, its efficacy in clinical settings, and its potential to alter pathological pathways. HHT demonstrates significant promise in treating various hematological malignancies and cancers, offering a multifaceted approach to disease management. Its ability to impact various physiological pathways opens new avenues for therapeutic applications. This review provides a consolidated foundation for future research and clinical applications of HHT in diverse medical fields.

ATP-Binding Cassette Subfamily G Member 2 in Acute Myeloid Leukemia: A New Molecular Target?

Despite the progress in the knowledge of disease pathogenesis and the identification of many molecular markers as potential targets of new therapies, the cure of acute myeloid leukemia remains challenging. Disease recurrence after an initial response and the development of resistance to old and new therapies account for the poor survival rate and still make allogeneic stem cell transplantation the only curative option. Multidrug resistance (MDR) is a multifactorial phenomenon resulting from host-related characteristics and leukemia factors. Among these, the overexpression of membrane drug transporter proteins belonging to the ABC (ATP-Binding Cassette)-protein superfamily, which diverts drugs from their cellular targets, plays an important role. Moreover, a better understanding of leukemia biology has highlighted that, at least in cancer, ABC protein's role goes beyond simple drug transport and affects many other cell functions. In this paper, we summarized the current knowledge of ABCG2 (formerly Breast Cancer Resistance Protein, BCRP) in acute myeloid leukemia and discuss the potential ways to overcome its efflux function and to revert its ability to confer stemness to leukemia cells, favoring the persistence of leukemia progenitors in the bone marrow niche and justifying relapse also after therapy intensification with allogeneic stem cell transplantation.

Effectiveness of chemotherapy using bortezomib combined with homoharringtonine and cytarabine in refractory or relapsed acute myeloid leukemia: a phase II, multicenter, prospective clinical trial

Background

Refractory/relapsed acute myeloid leukemia (R/R AML) has unsatisfactory outcomes even after allogeneic hematopoietic stem cell transplantation. Long-term survival is mainly influenced by complete remission (CR) rates after induction therapies.

Objectives

To investigate CR/CR with incomplete hematologic recovery (CRi) rates and adverse events with a new induction therapy (bortezomib, homoharringtonine, and cytarabine [BHA]) for patients with R/R AML.

Methods

We enrolled 21 patients with R/R AML (median age, 42 [range, 30-62] years), who received BHA for remission induction (bortezomib, 1.3 mg/m2/day on days 1 and 4; homoharringtonine, 4 mg/m2/day for 5 days, and cytarabine, 1.5 g/m2/day for 5 days). CR and adverse events were assessed.

Results

After one course of BHA, the CR/CRi and partial remission rates were 38.1% and 14.3%, respectively, with an overall response rate (ORR) of 52.4% in 21 patients. 9 of 21 patients harbored FLT3-ITD or FLT3-TKD mutations, and achieved either CR/CRi or ORR of 66.7% (P=0.03) by comparison with that in R/R AML without FLT3 mutation. After induction therapy, consolidation chemotherapy or allogeneic hematopoietic stem cell transplantation led to a one-year overall survival of 27.8% in all patients. One-year relapse-free survival was 50% in 8 patients who had achieved CR/CRi after one course of BHA. During induction, non-hematologic adverse events (grade 3/4) commonly were infection (90.5%), hypokalemia (14.4%), hypocalcemia (14.3%), and mucositis (9.5%). In patients achieving CR, the median time to neutrophil count >0.5×109/L and time to platelet count >20×109/L were 15 (13-17) days and 13 (13-18) days, respectively.

Conclusion

BHA chemotherapy regimen was safe and tolerable to serve as an induction therapy for R/R AML, particularly with FLT3 mutation. The higher CR/CRi rate will give a clue to determine a potentialeffectiveness of BHA for AML patients carrying FLT3 mutation in a further investigation.

Clinical trial registration

https://www.chictr.org.cn/, identifier ChiCTR2000029841.

ACC010, a novel BRD4 inhibitor, synergized with homoharringtonine in acute myeloid leukemia with FLT3-ITD

Bromodomain-containing protein 4 (BRD4) inhibitors have been clinically developed to treat acute myeloid leukemia (AML), but their application is limited by the possibility of drug resistance, which is reportedly associated with the activation of the WNT/β-catenin pathway. Meanwhile, homoharringtonine (HHT), a classic antileukemia drug, possibly inhibits the WNT/β-catenin pathway. In this study, we attempted to combine a novel BRD4 inhibitor (ACC010) and HHT to explore their synergistic lethal effects in treating AML. Here, we found that co-treatment with ACC010 and HHT synergistically inhibited cell proliferation, induced apoptosis, and arrested the cell cycle in FMS-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD)-positive AML cells in vitro, and significantly inhibiting AML progression in vivo. Mechanistically, ACC010 and HHT cooperatively downregulated MYC and inhibited FLT3 activation. Further, when HHT was added, ACC010-resistant cells demonstrated a good synergy. We also extended our study to the mouse BaF3 cell line with FLT3-inhibitor-resistant FLT3-ITD/tyrosine kinase domain mutations and AML cells without FLT3-ITD. Collectively, our results suggested that the combination treatment of ACC010 and HHT might be a promising strategy for AML patients, especially those carrying FLT3-ITD.

Therapeutic Targeting of FLT3 in Acute Myeloid Leukemia: Current Status and Novel Approaches

FMS-like tyrosine kinase 3 (FLT3) is mutated in approximately 30% of acute myeloid leukemia (AML) patients. The presence of FLT3-ITD (internal tandem duplication, 20-25%) mutation and, to a lesser extent, FLT3-TKD (tyrosine kinase domain, 5-10%) mutation is associated with poorer diagnosis and therapy response since the leukemic cells become hyperproliferative and resistant to apoptosis after continuous activation of FLT3 signaling. Targeting FLT3 has been the focus of many pre-clinical and clinical studies. Hence, many small-molecule FLT3 inhibitors (FLT3is) have been developed, some of which are approved such as midostaurin and gilteritinib to be used in different clinical settings, either in combination with chemotherapy or alone. However, many questions regarding the best treatment strategy remain to be answered. On the other hand, various FLT3-dependent and -independent resistance mechanisms could be evolved during FLT3i therapy which limit their clinical impact. Therefore, identifying molecular mechanisms of resistance and developing novel strategies to overcome this obstacle is a current interest in the field. In this review, recent studies of approved FLT3i and knowledge about major resistance mechanisms of clinically approved FLT3i's will be discussed together with novel treatment approaches such as designing novel FLT3i and dual FLT3i and combination strategies including approved FLT3i plus small-molecule agents targeting altered molecules in the resistant cells to abrogate resistance. Moreover, how to choose an appropriate FLT3i for the patients will be summarized based on what is currently known from available clinical data. In addition, strategies beyond FLT3i's including immunotherapeutics, small-molecule FLT3 degraders, and flavonoids will be summarized to highlight potential alternatives in FLT3-mutated AML therapy.

Ibrutinib Prevents Acute Lung Injury via Multi-Targeting BTK, FLT3 and EGFR in Mice

Ibrutinib has potential therapeutic or protective effects against viral- and bacterial-induced acute lung injury (ALI), likely by modulating the Bruton tyrosine kinase (BTK) signaling pathway. However, ibrutinib has multi-target effects. Moreover, immunity and inflammation targets in ALI treatment are poorly defined. We investigated whether the BTK-, FLT3-, and EGFR-related signaling pathways mediated the protective effects of ibrutinib on ALI. The intratracheal administration of poly I:C or LPS after ibrutinib administration in mice was performed by gavage. The pathological conditions of the lungs were assessed by micro-CT and HE staining. The levels of neutrophils, lymphocytes, and related inflammatory factors in the lungs were evaluated by ELISA, flow cytometry, immunohistochemistry, and immunofluorescence. Finally, the expression of proteins associated with the BTK-, FLT3-, and EGFR-related signaling pathways were evaluated by Western blotting. Ibrutinib (10 mg/kg) protected against poly I:C-induced (5 mg/kg) and LPS-induced (5 mg/kg) lung inflammation. The wet/dry weight ratio (W/D) and total proteins in the bronchoalveolar lavage fluid (BALF) were markedly reduced after ibrutinib (10 mg/kg) treatment, relative to the poly I:C- and LPS-treated groups. The levels of ALI indicators (NFκB, IL-1β, IL-6, TNF-α, IFN-γ, neutrophils, and lymphocytes) were significantly reduced after treatment. Accordingly, ibrutinib inhibited the poly I:C- and LPS-induced BTK-, FLT3-, and EGFR-related pathway activations. Ibrutinib inhibited poly I:C- and LPS-induced acute lung injury, and this may be due to its ability to suppress the BTK-, FLT3-, and EGFR-related signaling pathways. Therefore, ibrutinib is a potential protective agent for regulating immunity and inflammation in poly I:C- and LPS-induced ALI.

Developing therapeutic approaches for chronic myeloid leukemia: a review

Modern clinical therapy of chronic myeloid leukemia (CML) with TKIs is highly efficacious in most CML patients, while it is not remedial and generally confined due to intolerance or resistance. CML is currently considered a severe disease. Interestingly, stem cell transplantation in the past decade was an attractive clinical therapeutic option in CML patients, but it is not successful due to independently more death rates in older patients. So, the targeting of BCR::ABL oncoprotein is extensively used to enhance the reduction in a higher percentage of CML patients by tyrosine kinase inhibitors (TKIs). However, resistance or intolerance responses to these inhibitors are responsible for future deterioration and further development of disease. At this point, the clinical treatment of CML is a major challenge, and the lack of molecular responses to TKIs are not succeeded with chemotherapy alone. So, the considerable efficacious clinical necessities remain unmet. Therefore, continuous efforts are needed to explore new potential treatment strategies with an increasing understanding of CML biology. Therefore, this review deals with the investigation of TKI treatment with interferon, chemotherapy (Hydroxyurea, Homoharringtonine, Omacetaxine, Cytarabine), and several other new TKIs under beneficial clinical trials. Additionally, the approaches towards TKIs-resistant or intolerant CML cells where the respective signaling pathway gets up-regulated are also targeted with its inhibitor. This review presents evidence that new TKIs under clinical and pre-clinical trials may improve the chemotherapy of CML.

Homoharringtonine is a transdermal granular permeation enhancer

Although modulation of claudin-1-based tight junction (TJ) in stratum granulosum is an option for transdermal absorption of drugs, granular permeation enhancers have never been developed. We previously found that homoharringtonine (HHT), a natural alkanoid, weakened intestinal epithelial barrier with changing expression and cellular localization of TJ components such as claudin-1 and claudin-4. In the present study, we investigated whether HHT is an epidermal granular permeation enhancer. Treatment of normal human epidermal keratinocytes (NHEK) cells with HHT decreased claudin-1 and claudin-4 but not zonula occludens-1 and E-cadherin. HHT lowered TJ-integrity in NHEK cells, accompanied by permeation-enhancement of dextran (4 kDa) in a dose-dependent manner. Transdermal treatment of mice with HHT weakened epidermal barrier. HHT treatment enhanced transdermal absorption of dextran with a molecular mass of up to 10 kDa. Together, HHT may be a transdermal absorption enhancer.

The Metabolic Signature of AML Cells Treated With Homoharringtonine

Acute myeloid leukemia (AML) is a hematologic malignancy. The overall prognosis is poor and therapeutic strategies still need to be improved. Studies have found that abnormalities in metabolisms promote the survival of AML cells. In recent years, an increasing number of studies have reported the effectiveness of a protein synthesis inhibitor, homoharringtonine (HHT), for the treatment of AML. In this study, we demonstrated that HHT effectively inhibited AML cells, especially MV4-11, a cell line representing human AML carrying the poor prognostic marker FLT3-ITD. We analyzed the transcriptome of MV4-11 cells treated with HHT, and identified the affected metabolic pathways including the choline metabolism process. In addition, we generated a line of MV4-11 cells that were resistant to HHT. The transcriptome analysis showed that the resistant mechanism was closely related to the ether lipid metabolism pathway. The key genes involved in these processes were AL162417.1, PLA2G2D, and LPCAT2 by multiple intergroup comparison and Venn analysis. In conclusion, we found that the treatment of HHT significantly changed metabolic signatures of AML cells, which may contribute to the precise clinical use of HHT and the development of novel strategies to treat HHT-resistant AML.

TMEM16A, a Homoharringtonine Receptor, as a Potential Endogenic Target for Lung Cancer Treatment

Lung cancer has the highest rate of incidence and mortality among all cancers. Most chemotherapeutic drugs used to treat lung cancer cause serious side effects and are susceptible to drug resistance. Therefore, exploring novel therapeutic targets for lung cancer is important. In this study, we evaluated the potential of TMEM16A as a drug target for lung cancer. Homoharringtonine (HHT) was identified as a novel natural product inhibitor of TMEM16A. Patch-clamp experiments showed that HHT inhibited TMEM16A activity in a concentration-dependent manner. HHT significantly inhibited the proliferation and migration of lung cancer cells with high TMEM16A expression but did not affect the growth of normal lung cells in the absence of TMEM16A expression. In vivo experiments showed that HHT inhibited the growth of lung tumors in mice and did not reduce their body weight. Finally, the molecular mechanism through which HHT inhibits lung cancer was explored by western blotting. The findings showed that HHT has the potential to regulate TMEM16A activity both in vitro and in vivo and could be a new lead compound for the development of anti-lung-cancer drugs.